Name: _____________________________Date: ______________________Period: _____ Score: ________
Activity 61: Gene Squares
Vocabulary
166. Homozygous is …
167. Heterozygous is …
168. A Carrier is …
184. A Punnett square is …
Generation 1 Cross: Poppy and Skye
Skye: Blue tail - TT
Poppy: Orange tail - tt
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Describe the mating of Poppy and Skye using the
words from the vocabulary list.
Skye, a ________________________ blue tail
mated with Poppy, a ____________________
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orange tail. Their offspring were four
________________________ blue tails.
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Ratio of blue to orange: ________________
Offspring Genotypes
____________________________
Probability of blue tail: _______________
Probability of orange tail: ______________
Offspring Phenotypes
___________________________
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Generation 2 Cross: Ocean and Lucy
Phenotype
Genotype
Ocean: Blue tail – Tt
Describe the mating of Ocean and Lucy
using words from the vocabulary list.
Lucy: Blue tail - Tt
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Ratio of blue to orange:_______________
Offspring Genotypes
Probability of blue tail: _______________
__________________________
Probability of orange tail: _____________
Offspring Phenotypes
__________________________
Generation 3 Cross: _____________ and ___________ (Make up the names)
Phenotype
Genotype
_______:_________ – ___
_______:_________ – ___
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Describe the mating of any two generation 3
offspring using words from the vocabulary
list. (Feel free to name them yourself)
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Offspring Genotypes
___________________________
Ratio of blue to orange:_______________
Probability of blue tail: _______________
Probability of orange tail: _____________
Offspring Phenotypes
___________________________
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Cross: Rosy and Ralph
Phenotype
Genotype
Rosy : _________ – ___
Ralph : _________ – ___
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Use the Punnett Square to show the cross of:
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Rosy - a heterozygous curly haired cat
Ralph - a homozygous straight haired cat
Curly hair (H): Dominant
Straight hair (h): Recessive
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Offspring Genotypes
__________________________
Ratio of curly to straight: ______________
Offspring Phenotypes
Probability of curly hair: _______________
_________________________
Probability of straight hair: ______________
Cross: Feisty and Fluffy
Phenotype
Genotype
Feisty : __________ – ___
Fluffy : __________ – ___
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Use the Punnett Square to show the cross of:
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Feisty - a cat who is a carrier of the six toed gene
Fluffy - a cat who is a carrier of the six toed gene
5 toes (T): Dominant
6 toes (t): Recessive
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Offspring Genotypes
_________________________
Offspring Phenotypes
Ratio of 5 toes to 6 toes: ______________
Probability of five toes: _______________
Probability of six toes: ______________
_________________________
Pacific Cascade Science
Additional Punnett Square PracticeComplete the following crosses: Draw the resulting Punnett square, list the ratio and describe the
offspring’s genotype and phenotype. Be sure to remember that the capital letter is dominant.
Example: A green pea plant (GG) is being crossed with a green pea plant (Gg). Yellow is the
recessive color(g).
G
G
Genotype= 2 GG: 2 Gg: 0 gg
G
g
1.
Phenotype= 4 green pea plants: 0 yellow pea plants
Ratio: 1:1:0
A green pea plant (Gg) is crossed with a yellow pea plant (gg)
Genotype: _____________________
Phenotype: ____________________
Ratio: _________________________
2. A tall plant (TT) is crossed with a tall plant (Tt).
Genotype: ____________________
Phenotype: ___________________
Ratio: _______________________
3. A tall plant (Tt) is cross with a short plant (tt).
Genotype: ____________________
Phenotype: ___________________
Ratio: _______________________
4. A red flower (Rr) is crossed with a white flower (rr).
Genotype: ____________________
Phenotype: ___________________
Ratio: _______________________
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5. A white flower (rr) is crossed with a white flower (rr).
Genotype: ____________________
Phenotype: ___________________
Ratio: _______________________
6. A black chicken (BB) is crossed with a black chicken (BB).
Genotype: ____________________
Phenotype: ___________________
Ratio: _______________________
Extra Complicated: Two traits at a time.
Cross: Tiger and Pixie
The real world is way more complicated. Let’s make it harder with two traits at a time.
Use the Punnett Square to show the cross of:
Tiger – A heterozygous curly haired cat who is carrier of the six toed gene
Pixie - A heterozygous curly haired cat who is carrier of the six toed gene
Curly hair (H): Dominant
Straight hair (h): Recessive
5 toes (T): Dominant
6 toes (t): Recessive
Phenotype
Genotype
Tiger : __________________ – _______
Pixie : __________________ – _______
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Offspring Genotypes
Offspring Phenotypes
What is the probability that one of their offspring has straight hair and 6 toes? ________
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Wrap Up:
Explain what this activity has confirmed for you, what you are now aware of or how your thinking
has changed. (I used to think… but now I know…)
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What, if anything, needs clarification?
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Pacific Cascade Science